Microorganisms attached on the surface of an object do not exist independently, but form a biofilm together with other microorganisms in the characteristic structure. The biofilm, which appears to work in favor of the human as seen in the use of immobilized microorganisms, is conversely revealed to cause tooth decay and food contamination, and has been extensively studied in recent years.
The dental biofilm includes 700 species or more of bacteria and 108 or more bacteria are present per 1 mg of the dental biofilm. Of these, A. naeslundii has been receiving much attention in recent years as a key microorganism required when the initial stage plaque (cariogenic plaque) proceeds to the late stage plaque (periodontal disease plaque).
In the conventional periodontal disease prevention, the mainstream idea was to sterilize periodontal disease bacteria such as Porphyromonas gingivalis (hereinafter referred to as “P. gingivalis”) to inhibit the periodontal diseases. However, in reality, the periodontal disease foci are present with a biofilm deeply in the periodontal pocket, which prevents an antibacterial substance from permeation. Therefore, the conventional periodontal disease prevention fails to achieve an intended effect, and additionally always facing the risk of the resistant bacteria emergence. Thus, a safer and more effective prevention method has been in demand.
Also, mechanical removal such as brushing, and scaling, is believed to be the most effective method for inhibiting a biofilm, but it is difficult to practice suitable oral care using the current procedure for people having difficulties in such a mechanical control of dental biofilm such as the elderly in need of nursing care, whereby the development of biofilm removal procedures different from the convention procedures are in demand.
Short chain fatty acids (SCFA) such as butyric acid, are known to be present in a high concentration in the periodontal pocket and the dental plaque of periodontal disease patients, and the association thereof with the development and progress of the periodontal diseases became clear. In recent years, it was confirmed that acids such as SCFA produced by the periodontal disease bacteria such as P. gingivalis has a promoting effect on biofilm formation of A. naeslundii, and the studies on investigation of mechanism and pathogenic development control which targets this phenomenon are conducted (NIHON UNIVERSITY SCHOOL OF DENTISTRY, National Institute of Infectious Diseases, Japan).
In the present invention, with an attention on the influence by acids to the A. naeslundii biofilm formation, a substance, which is capable of inhibiting the biofilm formation depending on acids such as butyric acid thereby to inhibit the periodontal disease biofilm formation, was searched for, and a development of a novel periodontal disease biofilm inhibiting material with such substance was attempted.
An example of the literature regarding an oral composition exhibiting an antibacterial effect on the dental biofilm and an improvement effect on the gingivitis is PTL 1. PTL 1 discloses an oral composition containing (A) N-acylsarcosine or a salt thereof and (B) benzylisothiocyanate in a mass ratio (A)/(B) of 0.5 to 20, and also discloses that the oral composition has a good antibacterial effect on the dental biofilm causing the oral diseases and improvement effect on the gingivitis. However, PTL 1 does not disclose nor suggest any effects on the periodontal diseases.